Jessica E. Pease Preston T. Bean Timothy B. Grabowski Allison A. Pease 2022 <p><span>We used stable isotope analysis to investigate differences in Guadalupe bass (</span><i>Micropterus treculii</i><span>) resource use that might be associated with population-level variation in mainstem river versus tributary stream habitats. Guadalupe bass from mainstem sites had higher δ</span>¹³<span>C and δ</span>¹⁵<span>N values compared to those collected in tributaries, likely reflecting greater importance of algae as a basal resource and influences of urban wastewater in mainstem habitats. Documenting ecological variation across ecosystem types is important to inform fish conservation efforts, especially for species that occupy a range of stream sizes.</span></p> application/pdf 10.1002/rra.4015 en Wiley Endemic Guadalupe bass (Micropterus treculii) are supported by isotopically distinct resources in tributary versus mainstem river food webs article